Forum

Mapping

Posted: 2 March 2007, 12:32 PM
Greg, you are bang on with the notion of minimum size in the field!

Simon, I notice that you posted at 2:30 am. You must have been quite shit-faced by then, but still, against the odds, have come up with a valid point.

Paul I

Posted: 2 March 2007, 1:45 PM
Sorry about this... but just back-tracking a little, a third and important path sometimes taken in order to make the map clearer [enter 'C'] i forgot to expose, is simplification and generalisation. This should be and is usually used by most of our mappers with varying degrees. In my opinion (this phase appears to get you out of the deep preverbial, so I'll use it here quite liberally) there is a high risk of easily applying too much simplification, resulting in a map that people do not enjoy running on because of the bingo effect. If too much is left off (and it's a fine line in subtle terrain) the competitor can be confussed to the extent that he/she is even unsure if they are even where they think they are! Relocation can be very hard if required. The course setters can also run into problems finding suitable control sites. At least if the map errs on the overmapped, controllers can chose the more definate features. And the competitors can use their own simplification skill at will, which I think is part of the whole philosophy (that's a big word for me)of orienteering.

Svend

Posted: 2 March 2007, 3:35 PM
Paul
Firstly I find it difficult to understand what you write about map scales and symbol sizes - 1:7500 symbols for a 10000 scale map ????

OCAD automatically select the correct symbol size when you atart a new map file at the 10000 scale. However, some area symbols should retain the specification for the 15000 scale (symbol 211, sandy ground is one of them, and for some maps, also stony ground).

The ISOM 2000 reads:"Where practical the same dot screens as used at
1:15000 will give the most legible map and are therefore to be preferred."

The Australian Federations mapping page reads: "Screens retain the specification for 1:15000 maps".

Distinct vegetation boundary 416 is often overused in forested areas. The specification reads: "very distinct vegetation boundaries within the forest". Some mappers overlook the two words: "very distinct". I also think this symbol should retain the 15000
scale diminsions for 10000 scale maps.

Bryan

Posted: 2 March 2007, 3:52 PM
Some quick comments:
I prefer a more detailed map to one which is undermapped which as Paul says has an element of bingo to it.

My work is for a mapping company (Terralink) and I have worked in it for 22 years and I find the Orienteering standard of trying to gear all mapping to a 1:15000 scale as artificial and different to the rest of the Cartographic and mapping world. To me, if the symbols were geared towards a 1:10000 scale this would be more natural and conforming (and a bit easier for new people).

In the ISOM 2000 spectification section on scale and map size it says: 'Independent of scale, maps should be drawn with lines, line screens and symbol sizes as specified for the 1:15000 maps.' The operative word here is SHOULD not MUST. If care is taken and you don't go overboard (like creating a map very difficult to see the symbols) and for major events you get the ok from the IOF controller, I see no problem with using smaller symbols. We did this for WMOC 2000.

Paul I

Posted: 2 March 2007, 5:28 PM
Didn't intend to confuse anyone, I should not have stated 1:7500. The link here was only that the symbol sizes come out the same dimensions as a 1:7500 m but at a scale of 1:10000.
What I should have said was using 1:15000 symbol set and enlarging them 150% for a 1:10000 map does not seem to work well in all cases.
Correct me if I am wrong.

Svend

Posted: 2 March 2007, 6:58 PM
Thanks Paul for pointing out the website www.o-maps.com, very interesting. Orest Kotylo's comments on mapping certainly makes
sense but it appears to be a slow process for the IOF to make changes to the mapping specification.

Michael

Posted: 17 March 2007, 5:16 PM
Back from some fieldwork. Low priority apprentice work as some would have it as its a remap close to a city:-)) Had time to reflect on the symbol-size debate while grappling with numerous sand-dune knolls and depressions.

I welcome creative rule-breaking, but let's be conscious of where this is leading us. Orienteering started with government maps of 1:100,000, and there has been a steady demand for increased detail. This has led us to 1:15,000 today, and its hardly surprising that there's a demand for 1:10,000. And then, after a few years, 1:7500, and so on.

Wherever we are in this process, we can find areas where things will not fit. My statement about "no smallest knoll..." should really have been expressed as "no smallest SPACING of knolls..." Occasionally you can move features (displacement is allowed) but it's limited if there are other features nearby.

Now what's wrong with moving down this track? Cost. The increased detail puts up the time required for mapping. Mapping costs are already rising as weekend volunteers are replaced by paid mappers, and our expectations of quality rise. More details means more hours in the field and on the computer. Rogainers can navigate on a 1:50,000 map, why can't we enjoy ourselves on a 1:15,000 one?

Maybe we SHOULD move down this path. The mapmaking industry would benefit after all:-)) And I'd better make an admission. I'm making a sprint map of a detailed area, and I can't do it at 1:4-5000! Further debate welcomed:-))

Paul I

Posted: 17 March 2007, 6:23 PM
Sorry Michael, I never once suggested that close to the city re-maps are of low priority, I merely have a personal preference for other type of mapping because I have very limited time available for mapping work. If I were a professional mapper I would prefer a variety of mapping, big, small, town, bush whatever. My inference to those type of maps being for apprentices was not said as such, but only that those type of areas are suitable training maps for apprentice mappers. I wouldn't want you to get the wrong idea.

Kevin and I, having mapped many area's here and overseas back in the late 80's, early 90's, were always defending the right to produce 1:15000 maps because this was the International norm at the time and we didn't want our elite disadvantaged. We were always up against strong opposition preferring NZ to almost go alone in making 1:10000 maps standard.
Now that I have returned to orienteering and am still keen on mapping I see that 1:10000 is taking hold globally because orienteering event formats are demanding more detail on their maps. Having an open mind on this subject, I am happy with 1:10000 as my experience of mapping overseas tells me that we kiwis have always mapped at more detail, this was admired overseas and infact started a trend to follow suit.
I do note however that the IOF still suggests that the standard scale for long distance orienteering should be at 1:15000, unless the area is too complex.
I'm sure your sprint map will be fine, the new specs look to have some very fine tools to use. Greg's Massey University sprint map was very detailed, including each and every stair as well as some detail under canapies. The resulting map and cartography was fantastic.

The cost is another issue that needs to be addressed. It may be a quantity verses quality issue, or may be a event price issue, a sponsorship thing or whatever, but I think a map should always display its character, especially if it is technically complex. And most definately mappers such as yourself need to be paid reasonably well for your efforts or we will struggle to make any more big maps.

It would be quite interesting to know how you coped with the detailed knoll/depression sand-dune terrain you mentioned as this is one of the most difficult and controversial problems mappers still have. It would also be helpfull to have the opinions of todays elite, who experience maps overseas to compare with.

ole codger

Posted: 18 March 2007, 9:33 AM
I don't really agree with Paul that remaps are suitable for apprentices. I,ve worked on quite few remaps and it takes experience to make judgement that relativity may not be right in some areas. Indeed sometimes you need to go back to the original photogrammetry (never disgard it, even hough you may have the map on OCAD)to discern which are the correctly mapped features.We are working on a 1981 Steve Key map (Steve was Aust. leading mapper and went onto map the USA World champs) and while he made a good map in some areas from what was poor photogrammetry(Swedish firm)he fell into the trap of believing the base map 100%in one instance and placed 2 hills on the end of a flatish 125m spur given on the photogrammetry.As there was not much else to work from in a flatish area mapping continued as though they were the correct relative feature to work from. In actual fact they were 47 m further up the spur from were the photogrametry ran slightly down hill and this was not discovered until features did not matchup from another direction. The area had to be fieldworked again with the hills correctly placed and the end of the spur shaped by a form line. I doubt if an apprentice would have pick up on this.
Give me a virgin (map)anyday to work on.

Paul I

Posted: 18 March 2007, 4:33 PM
Hi ole codger ! The problem I suppose with this forum is that every little thing you say can get picked apart. I suppose it is quite entertaining anyhow. I wasn't really discussing apprentice mappers at any detail, it was originally in general discussion saying that I personally, like yourself would prefer to deal with a virgin map than fix someone elses screwups ! (not that I might not make any myself). I agree with you that remaps can be hardwork too, a really poor map would indeed require someone with experience to sort it out. But I don't believe either that it would be a good idea to send anyone without a proven vast mapping experience to attempt a map like White Lightening, as much of the photogrammetry was very difficult to use and did not show a lot of detail.
Anyhow it's good to have another mapper speak out because if we don't swap opinions or ideas nothing ever changes and we get stuck in ruts. Where are the rest of us? Today I went out doing some control site checking, I was with the course setter and we came across a few areas requiring map corrections. It was very helpfull to have someone else there to discuss the situation with and see their point of view,. It made me think that all mappers really should do some map walks together more often, along with apprentice and interested mappers.
I'm looking foward to your remap of Waiuku and had been wondering how the mapping styles of way back then compare with today, and whether the 1:10000 scale will be more suitable.

Michael

Posted: 18 March 2007, 10:40 PM
Can I rephrase what I wrote above? I welcome creative EXPERIMENTATION, not rule-breaking. We have B-level events and below where things may not be strictly to the rules. A-level events should comply with the rules I reckon. Which isn't to say the rules should never change, but only after due process.

The mapwalk idea is good Paul, we've been saying for years we must hold some advanced mapping get-togethers. There's nothing I can say on a forum like this about how I cope with remapping in detailed sand-dune terrain. Except to say that taking off the knolls and depressions that are under 1m deep/high is a good start:-)) And I reckon that if I'm in some doubt about whether a feature should make it onto the map, then "off" is usually the best answer.

Ole Codger, ditto to your comments about questioning position. In spite of the attraction of virgin areas, the big need facing us is fixing existing maps. It was like this in software development too - everyone wanted to write new software, the big need is in maintenance.

Paul I

Posted: 19 March 2007, 12:56 PM
We ought to compile a list of those who do enough mapping in NZ and through correspondence set up a mapwalk or two. I know you've tried before Michael, but we should keep trying. Those who attend will be the beneficiaries.
Sand dune terrain should be our focus. We are using three sand dune maps over the nationals extended w-end, Waiuku, Stags Roar, White Lightening, so maybe this is our opportunity while most people will be attending these events. I know it may be a bit of a pain in the preverbial, ie; I have my family to fend off, so these walk/discussions don't need to be too long.
One concern that arrises is that we probably all do not want our mapping work scrutinised by our peers for all to see, so are a little reluctant, we need to remember that we are all human, we all make mistakes, we all have good and bad days and MOST IMPORTANTLY no one way of mapping is ever the only right way. Experiments have shown that most people see terrain slightly diffirent from each other. Our aim should be to be more consistant. A nuetral map could alleviate awkwardness but is probably harder to get organised. The last thing that needs to happen is that it turns into a heated debate as we defend our differing views!
We could try to walk aimlessly through the map commenting on observations, visit problem areas that we thought were either over or under mapped, and anything else that we can think of. I don't think at this stage it needs to be as formal as a mapping clinic.
Anyone interested?

Michael

Posted: 19 March 2007, 1:43 PM
Yes me. I'll be around during the week after Easter altho locals will probably be working. An off-map meeting (evening) may also be useful, as I said I always learn things when I visit Jim Lewis. The recent meeting I set up at Waitangi Weekend had two participants - Jim and me:-))

Mapping SHOULD be scrutinised for all to see. Areas of interest are those which gave competitors trouble (to find out why). And areas which gave the mapper trouble (if they turned out fine, that's also valuable to learn from). It may not be easy to find such spots in close proximity, as the majority of most maps may not fall into either category.

Paul I

Posted: 19 March 2007, 5:15 PM
I can think of many areas on white Lightening that as a mapper presented difficulties, and also areas I had trouble on as a runner.
I'll be there on the WEnd following Nationals, but not mid week.
I'll be working during the week, in the evenings/nights, so unfortunately can't meet up then (unless its really raining cats and dogs).
It would also probably be more beneficial to look at more than one map.

Who are the mappers we need to get on board? I think we all have a responsibility, as a group of paid contractors working for orienteering organisations, make an effort here to meet very occasionally to discuss matters. As I have said, I'm not really aware of all of the mappers these days, obviously us two, Jim, the Aspins, Mike B, Teahans, Robbie ... there must be heaps more. Can we set a couple of dates and contact everyone.

These are just my ideas, maybe there are other possibilities to suit others?

Greg

Posted: 19 March 2007, 8:19 PM
Theres some good sprint issues on the new Massey University Map (western part different to last queens b'day) which I've done. Some really complex canopies and walkways with walls, gardens etc.

Good plug for the After Match Sprint on Wed 11th as well It will be awesome